Improvement of detectable sensitivity for enzyme reaction by scanning electrochemical microscopy with distance control system for immunosensing

Abstract

Detectable sensitivity for immobilized enzymes was improved using a constant-distance mode of scanning electrochemical microscopy (SECM). Redox species generated by an enzyme reaction captured via irmmunorecognition were detected with a microelectrode used as a probe. The probe maintained considerably close to the target surface (50 nm) allowed the enhancement of the current response because of cycling of redox species between the probe and the captured enzymes. The sensitivity of di(n-butyl)phthalate detection with a competitive assay by using constant-distance mode SECM was at least one order of magnitude higher than that of the probe scanned in a constant z-position. © The Electrochemical Society of Japan, All rights reserved.